1. Field of the Invention
The present invention relates to stringed musical instruments, particularly guitars, and, more particularly, guitars having tremolo devices, that is, devices for rapidly changing the string tension so as to produce a tremulous tone effect.
2. Prior Art
At the soundboard or body end portion of a guitar, the guitar strings are anchored to a bridge which, in some guitars, can be manually reciprocated or oscillated relative to the guitar body so as to change the string tension and produce a tremulous tone effect. Between the head and neck positions of the guitar, the strings pass over the nut which usually is grooved to receive the strings. Manipulation of the tremolo device can cause a string to slide over the nut. Friction can prevent the string from returning to precisely the same position as prior to manipulation of the tremolo device, with the result being that the guitar no longer is in tune.
Rose U.S. Pat. No. 4,171,661 discloses "string restraining means" for clamping opposite end portions of the guitar strings against the nut and the bridge, respectively, so as to prevent this type of sliding movement. In the Rose mechanism, a rigid bar extending over two adjacent strings is secured into the nut so as to clamp the two strings between the bar and the nut. At the bridge end a separate block is provided for each string to clamp it between the block and the bridge.
For a conventional guitar having six strings, three separate bars of the Rose design must be loosened so that the guitar can be tuned by use of the conventional screw or worm tension-adjusting mechanism to which the strings are anchored at the head of the guitar. To replace a string, the clamping block at the bridge end also must be loosened or removed.
An additional problem with known guitars fitted with tremolo devices is that altering the tension of an individual string may result in changing the tensions of all of the other strings. A skilled musician can force a string transversely of the neck of the guitar so as to alter the string tension, but for a guitar fitted with a conventional tremolo device, altering the tension of one string in this manner may cause movement of the movable bridge which changes the tensions of all of the other strings.
A further problem with known guitars fitted with tremolo devices is that there is high friction between the movable bridge and the guitar body so that the bridge may not always return to precisely the same position. In the Rose device, for example, concave cutouts are provided in the forward end of the opposite lateral sides of a movable bridge plate, which cutouts are fitted beneath the heads of screws projecting up from the guitar body. As best seen in FIG. 4 of the Rose patent, the forward end of the bridge plate is pinched between the tapered screw heads and nuts or "flanged shoulders" immediately beneath the screw heads.